【正文】 I 摘 要 本系統(tǒng)由單片機(jī)程控設(shè)定數(shù)字信號(hào)，經(jīng)過 D/A 轉(zhuǎn)換器 AD5320 輸出模擬量，控制輸出功率管的基極，隨著功率管基極電壓的變化而輸出不同的電流。單片機(jī)系統(tǒng)還兼顧對(duì)恒流源進(jìn)行實(shí)時(shí)監(jiān)控，輸出電流經(jīng)過電流 /電壓轉(zhuǎn)換后 ，通過 A/D 轉(zhuǎn)換芯片 MAX1241，實(shí)時(shí)把模擬量轉(zhuǎn)化為數(shù) 字 量，再經(jīng)單片機(jī)分析處理，通過數(shù)字量形式的反饋環(huán)節(jié)，使電流更加穩(wěn)定，這樣構(gòu)成穩(wěn)定的壓控電流源。 關(guān)鍵詞： 壓控恒流源 ； AT89S52； 數(shù)控電源； Abstract In the system, the digitally programmable signal from SCM is converted to analog value by DAC AD5320, is sent to the base electrode of power transistor, so an adjustable output current can be available with the base electrode voltage of power transistor. On the other hand, The constant current source can be monitored by the SCM system realtimely, its work process is that output current is converted voltage, then its analog value is converted to digital value by ADC MAX1241, finally the digital value as a feedback loop is processed by SCM so that output current is more stable, so a stable voltagecontrolled constant current power is designed. KeyWords： voltagecontrolled constant current source； AT89S52； Numerical controlled source； II 目 錄 摘 要 ............................................................................................................................ I Abstract .............................................................................................................................. I 引 言 ........................................................................................................................... 1 第一章 概述 ................................................................................................................... 2 設(shè)計(jì)要求 ..................................................................................................... 2 理論分析 ..................................................................................................... 2 系統(tǒng)介紹 ..................................................................................................... 2 第二章 硬件設(shè)計(jì) ........................................................................................................... 4 電源模塊 ..................................................................................................... 4 電源設(shè)計(jì) ......................................................................................... 4 恒流源模塊 ................................................................................................. 5 單片機(jī)模塊 ................................................................................................. 5 AT89S52 芯片介紹 ........................................................................ 5 AT89S52 硬件電路設(shè)計(jì) ............................................................... 8 鍵盤模塊 ..................................................................................................... 9 MM74C922 ..................................................................................... 9 鍵盤電路 ......................................................................................... 9 顯示模塊 ................................................................................................... 10 1602LCD 顯示 .............................................................................. 10 LCD 顯示硬件電路 ...................................................................... 11 A/D 模塊 ................................................................................................. 11 芯片 MAX1241 ............................................................................ 11 A/D 模塊電路 ............................................................................... 12 D/A 模塊 ................................................................................................. 13 存儲(chǔ)模塊 ................................................................................................... 13 2? C 總線 ....................................................................................... 13 芯片 24C02C ................................................................................ 14 存儲(chǔ)模塊電路 ............................................................................... 14 第三章 軟件設(shè)計(jì) ......................................................................................................... 15 編程語言描述 ........................................................................................... 15 系統(tǒng)軟件的功能模塊 ............................................................................... 15 主程序設(shè)計(jì) ................................................................................... 15 中斷程序設(shè)計(jì) ............................................................................... 16 第四章 軟件仿真及硬件調(diào)試 ..................................................................................... 21 Proteus..................................................................................................... 21 軟件仿真 ................................................................................................... 21 硬件調(diào)試 ................................................................................................... 22 單片機(jī)最小系統(tǒng)調(diào)試 ................................................................... 22 鍵盤及液晶顯示調(diào)試 ................................................................... 22 數(shù)模轉(zhuǎn)換與功放電路調(diào)試 ........................................................... 22 模數(shù)轉(zhuǎn)換電路調(diào)試 ....................................................................... 22 存儲(chǔ)器電路調(diào)試 ........................................................................... 22 第五章 設(shè)計(jì)總結(jié) ......................................................................................................... 24 III 致謝 ................................................................................................................................. 25 參考文獻(xiàn) ........................................................................................